Two studies, both in overweight subjects, confirmed the safety of the ellagitannin-rich pomegranate extract, with no adverse effects reports, and showed a significant reduction in thiobarbituric acid reactive substances (TBARS) in the blood linked with cardiovascular disease risk.
The findings were published in the Journal of Agricultural and Food Chemistry .
According to the authors, formulations containing pomegranate extracts are commercially available in dietary supplements, but, until now, no studies have reported the safety of such extracts in human subjects.
Pomegranate, a rich source of antioxidants, has been linked to improved heart health, but a growing body of science indicates the fruit protect against prostate cancer and slowing cartilage loss in arthritis.
It is these antioxidants, and particularly ellagitannin compounds like punicalagins and punicalins, which accounts for about half of the fruit's antioxidant ability, that are reportedly behind the proposed health benefits.
Lead author David Heber from the University of California, Los Angeles (UCLA), in collaboration with researchers from the University of Colorado and Pom Wonderful, recruited 64 overweight individuals with increased waist size to take part in the safety study, and a further 22 overweight subjects for the study to measure the effects on TBARS.
Overweight, but otherwise healthy, subjects were chosen because excess abdominal fat has been associated with increased inflammation and oxidative stress, said the researchers.
The first of the two pilot clinical studies assigned the 64 to receive either one or two capsules per day giving daily extract doses of 710 mg (435 mg of gallic acid equivalents, GAEs) or 1420 mg (870 mg of GAEs), respectively, and placebo.
The commercially available POMx supplement was used (Pom Wonderful, California).
No major adverse effects were reported during the 30 days.
Some minor adverse events were reported but none deemed related to the supplement.
Moreover, no significant changes occurred in measures of complete blood count (CBC), chemistry, and urinalysis.
In the second trial, 22 subjects received two POMx capsules providing 1000 mg of extracts per day (610 mg of GAEs).
Heber and co-workers report The researchers did note an increase in body weight among the subjects, however.
This could be attributed to the timing of the study, which coincided with end of autumn and several important US holidays.
A significant decrease of 0.13 micromoles in TBARS was observed in these subjects, they report.
TBARS is considered an important biomarker for oxidative stress, and is strongly linked to cardiovascular events.
"Further studies are underway to document the effects of this supplement in subjects with type 2 diabetes, known to have a more marked increase in oxidant stress," wrote the authors.
"This research was part of POMx's new dietary ingredient (NDI) safety submission, which to the best of our knowledge is currently the only pomegranate dietary supplement to be submitted to the U.S. Food and Drug Administration (FDA)," They added.
Source: Journal of Agricultural and Food Chemistry 28 November 2007, Volume 55, Number 24, Pages 10050-10054.
"Safety and antioxidant activity of a pomegranate ellagitannin-enriched polyphenol dietary supplement in overweight individuals with increased waist size" Authors: D. Heber, N.P. Seeram, H. Wyatt, S.M. Henning, Y. Zhang, L.G. Ogden, M. Dreher, J.O. Hill